<HTML><HEAD><TITLE>All_About_Your_64-Online-Help Version 0.64</TITLE></HEAD>
<BODY><PRE>

  +------------------------------------------------------------------------
  |
  |      ZEROPAGE AND EXTENDED ZEROPAGE - DESCRIPTIONS
  |
  +------------------------------------------------------------------------
  |
  | Zeropage:
  |
  |   <A HREF="ZP00.HTM">$00/0</A>                   6510 On-chip Data Direction Register
  |   <A HREF="ZP01.HTM">$01/1</A>                   6510 On-chip 8-bit Input/Output Register
  |   <A HREF="ZP02.HTM">$02/2</A>                   Unused
  |   <A HREF="ZP03.HTM">$03-$04/3-4</A>             Jump Vector: Convert FAC to Integer
  |   <A HREF="ZP05.HTM">$05-$06/5-6</A>             Jump Vector: Convert Integer to Floating point
  |   <A HREF="ZP07.HTM">$07/7</A>                   Search Character/Temporary Integer during INT
  |   <A HREF="ZP08.HTM">$08/8</A>                   Flag: Scan for Quote at end of String
  |   <A HREF="ZP07.HTM">$07-$08/7-8</A>             Temporary Integer during OR/AND
  |   <A HREF="ZP09.HTM">$09/9</A>                   Screen Column for last TAB
  |   <A HREF="ZP0A.HTM">$0A/10</A>                  Load/Verify-Flag
  |   <A HREF="ZP0B.HTM">$0B/11</A>                  Input Buffer Pointer/Number of Subscripts
  |   <A HREF="ZP0C.HTM">$0C/12</A>                  Flag: Default Array dimension
  |   <A HREF="ZP0D.HTM">$0D/13</A>                  Data type Flag
  |   <A HREF="ZP0E.HTM">$0E/14</A>                  Data type Flag
  |   <A HREF="ZP0F.HTM">$0F/15</A>                  Flag: DATA scan/List Quote/Garbage collection
  |   <A HREF="ZP10.HTM">$10/16</A>                  Flag: Subscript reference/User Function call
  |   <A HREF="ZP11.HTM">$11/17</A>                  Input Flag
  |   <A HREF="ZP12.HTM">$12/18</A>                  Flag: TAN sign/Comparative result
  |   <A HREF="ZP13.HTM">$13/19</A>                  File number of current Input Device
  |   <A HREF="ZP14.HTM">$14-$15/20-21</A>           Temporary: Integer value
  |   <A HREF="ZP16.HTM">$16/22</A>                  Pointer: Temporary String Stack
  |   <A HREF="ZP17.HTM">$17-$18/23-24</A>           Last temporary String Address
  |   <A HREF="ZP19.HTM">$19-$21/25-33</A>           Stack for temporary Strings
  |   <A HREF="ZP22.HTM">$22-$25/34-37</A>           Utility Pointer Area
  |   <A HREF="ZP22.HTM">$22-$23/34-35</A>           First Utility Pointer
  |   <A HREF="ZP22.HTM">$24-$25/36-37</A>           Second Utility Pointer
  |   <A HREF="ZP26.HTM">$26-$2A/38-42</A>           Floating point product of Multiply and Divide
  |   <A HREF="ZP2B.HTM">$2B-$2C/43-44</A>           Pointer: Start of BASIC Text Area
  |   <A HREF="ZP2D.HTM">$2D-$2E/45-46</A>           Pointer: Start of BASIC Variables
  |   <A HREF="ZP2F.HTM">$2F-$30/47-48</A>           Pointer: Start of BASIC Arrays
  |   <A HREF="ZP31.HTM">$31-$32/49-50</A>           Pointer: End of BASIC Arrays + 1
  |   <A HREF="ZP33.HTM">$33-$34/51-52</A>           Pointer: Bottom of String space
  |   <A HREF="ZP35.HTM">$35-$36/53-54</A>           Utility String Pointer
  |   <A HREF="ZP37.HTM">$37-$38/55-56</A>           Pointer: Highest Address available to BASIC
  |   <A HREF="ZP39.HTM">$39-$3A/57-58</A>           Current BASIC Line number
  |   <A HREF="ZP3B.HTM">$3B-$3C/59-60</A>           Previous BASIC Line number
  |   <A HREF="ZP3D.HTM">$3D-$3E/61-62</A>           Pointer: BASIC Statement for CONT
  |   <A HREF="ZP3F.HTM">$3F-$40/63-64</A>           Current DATA Line number
  |   <A HREF="ZP41.HTM">$41-$42/65-66</A>           Pointer: Used by READ - current DATA Item
  |   <A HREF="ZP43.HTM">$43-$44/67-68</A>           Pointer: Temporary storage during INPUT
  |   <A HREF="ZP45.HTM">$45-$46/69-70</A>           Name of Variable being sought in Variable Table
  |   <A HREF="ZP47.HTM">$47-$48/71-72</A>           Value/Descriptor-Pointer
  |   <A HREF="ZP49.HTM">$49-$4A/73-74</A>           Pointer: Index Variable for FOR/NEXT loop
  |   <A HREF="ZP4B.HTM">$4B-$4C/75-76</A>           Temporary storage for TXTPTR
  |   <A HREF="ZP4D.HTM">$4D/77</A>                  Mask used during FRMEVL
  |   <A HREF="ZP4E.HTM">$4E-$52/78-82</A>           Temporary storage for FLPT value
  |   <A HREF="ZP53.HTM">$53/83</A>                  Length of String during Garbage collection
  |   <A HREF="ZP54.HTM">$54-$56/84-86</A>           Jump Vector used in Function Evaluation
  |   <A HREF="ZP57.HTM">$57-$5B/87-91</A>           Temporary storage for FLPT value
  |   <A HREF="ZP5C.HTM">$5C-$60/92-96</A>           Temporary storage for FLPT value
  |   <A HREF="ZP61.HTM">$61-$66/97-102</A>          Main Floating point Accumulator
  |   <A HREF="ZP61.HTM">$61/97</A>                  FAC Exponent
  |   <A HREF="ZP62.HTM">$62-$65/98-101</A>          FAC Mantissa
  |   <A HREF="ZP66.HTM">$66/102</A>                 FAC Sign
  |   <A HREF="ZP67.HTM">$67/103</A>                 Pointer: Series Evaluation Constant
  |   <A HREF="ZP68.HTM">$68/104</A>                 Bit Overflow Area during normalisation Routine
  |   <A HREF="ZP69.HTM">$69-$6E/105-110</A>         Auxiliary Floating point Accumulator
  |   <A HREF="ZP69.HTM">$69/105</A>                 AFAC Exponent
  |   <A HREF="ZP6A.HTM">$6A-$6D/106-109</A>         AFAC Mantissa
  |   <A HREF="ZP6E.HTM">$6E/110</A>                 AFAC Sign
  |   <A HREF="ZP6F.HTM">$6F/111</A>                 Sign of result of Arithmetic Evaluation
  |   <A HREF="ZP70.HTM">$70/112</A>                 FAC low-order rounding
  |   <A HREF="ZP71.HTM">$71-$72/113-114</A>         Pointer: Used during CRUNCH/ASCII conversion
  |   <A HREF="ZP73.HTM">$73-$78/115-120</A>         CHRGET: Get next Byte of BASIC Text
  |   <A HREF="ZP79.HTM">$79-$8A/121-138</A>         CHRGOT: Get same Byte again
  |   <A HREF="ZP7A.HTM">$7A-$7B/122-123</A>         Pointer: Current Byte of BASIC Text
  |   <A HREF="ZP8B.HTM">$8B-$8F/139-143</A>         Floating RND Function Seed Value
  |   <A HREF="ZP90.HTM">$90/144</A>                 Kernal I/O Status Word ST
  |   <A HREF="ZP91.HTM">$91/145</A>                 Flag: $7F = STOP key
  |   <A HREF="ZP92.HTM">$92/146</A>                 Timing Constant for Tape
  |   <A HREF="ZP93.HTM">$93/147</A>                 Flag: 0 = Load, 1 = Verify
  |   <A HREF="ZP94.HTM">$94/148</A>                 Flag: Serial Bus - Output Character buffered
  |   <A HREF="ZP95.HTM">$95/149</A>                 Buffered Character for Serial Bus
  |   <A HREF="ZP96.HTM">$96/150</A>                 Cassette Sync number
  |   <A HREF="ZP97.HTM">$97/151</A>                 Storage of X Register during CHRIN
  |   <A HREF="ZP97.HTM">$97/151</A>                 Storage of Y Register during RS232 fetch
  |   <A HREF="ZP98.HTM">$98/152</A>                 Number of Open Files/Index to File Table
  |   <A HREF="ZP99.HTM">$99/153</A>                 Default Input Device (0)
  |   <A HREF="ZP9A.HTM">$9A/154</A>                 Default Output Device (3)
  |   <A HREF="ZP9B.HTM">$9B/155</A>                 Parity of Byte Output to Tape
  |   <A HREF="ZP9C.HTM">$9C/156</A>                 Flag: Byte received from Tape
  |   <A HREF="ZP9D.HTM">$9D/157</A>                 Error-Mode-Flag
  |   <A HREF="ZP9E.HTM">$9E/158</A>                 Index to Tape File name/Header ID for Tape write
  |   <A HREF="ZP9E.HTM">$9E/158</A>                 Tape Error log pass 1
  |   <A HREF="ZP9F.HTM">$9F/159</A>                 Tape Error log pass 2
  |   <A HREF="ZPA0.HTM">$A0-$A2/160-162</A>         Real-time jiffy Clock
  |   <A HREF="ZPA3.HTM">$A3/163</A>                 Bit Counter Tape Read or Write
  |   <A HREF="ZPA3.HTM">$A3/163</A>                 Serial Bus EOI (End Of Input) Flag
  |   <A HREF="ZPA4.HTM">$A4/164</A>                 Pulse Counter Tape Read or Write
  |   <A HREF="ZPA4.HTM">$A4/164</A>                 Serial Bus shift Counter
  |   <A HREF="ZPA5.HTM">$A5/165</A>                 Tape Synchronising count down
  |   <A HREF="ZPA6.HTM">$A6/166</A>                 Pointer: Tape I/O buffer
  |   <A HREF="ZPA7.HTM">$A7/167</A>                 RS232 temporary for received Bit
  |   <A HREF="ZPA7.HTM">$A7/167</A>                 Tape temporary
  |   <A HREF="ZPA8.HTM">$A8/168</A>                 RS232 Input Bit count/Tape temporary
  |   <A HREF="ZPA9.HTM">$A9/169</A>                 RS232 Flag: Start Bit check/Tape temporary
  |   <A HREF="ZPAA.HTM">$AA/170</A>                 RS232 Input Byte Buffer/Tape temporary
  |   <A HREF="ZPAB.HTM">$AB/171</A>                 RS232 Input parity/Tape temporary
  |   <A HREF="ZPAC.HTM">$AC-$AD/172-173</A>         Pointer: Tape Buffer/Screen scrolling
  |   <A HREF="ZPAE.HTM">$AE-$AF/174-175</A>         Tape End Address/End of Program
  |   <A HREF="ZPB0.HTM">$B0-$B1/176-177</A>         Tape timing Constants
  |   <A HREF="ZPB2.HTM">$B2-$B3/178-179</A>         Pointer: Start Address of Tape Buffer
  |   <A HREF="ZPB4.HTM">$B4/180</A>                 RS232 Write bit count/Tape Read timing Flag
  |   <A HREF="ZPB5.HTM">$B5/181</A>                 RS232 Next Bit to send/Tape Read - End of Tape
  |   <A HREF="ZPB6.HTM">$B6/182</A>                 RS232 Output Byte Buffer/Tape Read Error Flag
  |   <A HREF="ZPB7.HTM">$B7/183</A>                 Number of Characters in Filename
  |   <A HREF="ZPB8.HTM">$B8/184</A>                 Current File - Logical File number
  |   <A HREF="ZPB9.HTM">$B9/185</A>                 Current File - Secondary Address
  |   <A HREF="ZPBA.HTM">$BA/186</A>                 Current File - First Address (Device number)
  |   <A HREF="ZPBB.HTM">$BB-$BC/187-188</A>         Pointer: Current File name Address
  |   <A HREF="ZPBD.HTM">$BD/189</A>                 RS232 Output Parity/Tape Byte temporary
  |   <A HREF="ZPBE.HTM">$BE/190</A>                 Tape Input/Output Block count
  |   <A HREF="ZPBF.HTM">$BF/191</A>                 Serial Word Buffer
  |   <A HREF="ZPC0.HTM">$C0/192</A>                 Tape Motor Switch
  |   <A HREF="ZPC1.HTM">$C1-$C2/193-194</A>         Start Address for LOAD and Cassette Write
  |   <A HREF="ZPC3.HTM">$C3-$C4/195-196</A>         Pointer: Type 3 Tape LOAD and general use
  |   <A HREF="ZPC5.HTM">$C5/197</A>                 Matrix value of last Key pressed
  |   <A HREF="ZPC6.HTM">$C6/198</A>                 Number of Characters in Keyboard Buffer queue
  |   <A HREF="ZPC7.HTM">$C7/199</A>                 Flag: Reverse On/Off
  |   <A HREF="ZPC8.HTM">$C8/200</A>                 Pointer: End of Line for Input
  |   <A HREF="ZPC9.HTM">$C9-$CA/201-202</A>         Cursor X/Y position at start of Input
  |   <A HREF="ZPC5.HTM">$CB/203</A>                 Matrix value of last Key pressed
  |   <A HREF="ZPCC.HTM">$CC/204</A>                 Flag: Cursor blink
  |   <A HREF="ZPCD.HTM">$CD/205</A>                 Timer: Count down for Cursor blink toggle
  |   <A HREF="ZPCE.HTM">$CE/206</A>                 Character under Cursor while Cursor Inverted
  |   <A HREF="ZPCF.HTM">$CF/207</A>                 Flag: Cursor Status
  |   <A HREF="ZPD0.HTM">$D0/208</A>                 Flag: Input from ...
  |   <A HREF="ZPD1.HTM">$D1-$D2/209-210</A>         Pointer: Current Screen Line Address
  |   <A HREF="ZPD3.HTM">$D3/211</A>                 Cursor Column on current Line
  |   <A HREF="ZPD4.HTM">$D4/212</A>                 Flag: Editor in Quote Mode
  |   <A HREF="ZPD5.HTM">$D5/213</A>                 Current logical Line length: 39 or 79
  |   <A HREF="ZPD6.HTM">$D6/214</A>                 Current Screen Line number of Cursor
  |   <A HREF="ZPD7.HTM">$D7/215</A>                 Current Input Character/Last Character Output
  |   <A HREF="ZPD8.HTM">$D8/216</A>                 Count of number of inserts outstanding
  |   <A HREF="ZPD9.HTM">$D9-$F2/217-242</A>         Screen Line Link Table
  |   <A HREF="ZPF3.HTM">$F3-$F4/243-244</A>         Pointer: Current Color RAM Location
  |   <A HREF="ZPF5.HTM">$F5-$F6/245-246</A>         Vector: Current Keyboard decoding Table
  |   <A HREF="ZPF7.HTM">$F7-$F8/247-248</A>         RS232 Input Buffer Pointer
  |   <A HREF="ZPF9.HTM">$F9-$FA/249-250</A>         RS232 Output Buffer Pointer
  |   <A HREF="ZPFB.HTM">$FB-$FE/251-254</A>         Free ZeroPage space for User Programs
  |   <A HREF="ZPFF.HTM">$FF/255</A>                 BASIC temporary Data Area
  |   <A HREF="ZPFF.HTM">$FF-$010A/255-266</A>       Assembly Area for Floating point to ASCII
  |
  | Extended Zeropage:
  |
  |   <A HREF="ZP0100.HTM">$0100-$013E/256-318</A>     Tape Input Error log
  |   <A HREF="ZP0100.HTM">$0100-$01FF/256-511</A>     6510 Hardware Stack Area
  |   <A HREF="ZP013F.HTM">$013F-$01FF/319-511</A>     BASIC Stack Area
  |   <A HREF="ZP0200.HTM">$0200-$0258/512-600</A>     BASIC Input Buffer (Input Line from Screen)
  |   <A HREF="ZP0259.HTM">$0259-$0262/601-610</A>     Active logical File numbers
  |   <A HREF="ZP0263.HTM">$0263-$026C/611-620</A>     Active File First Addresses (Device numbers)
  |   <A HREF="ZP026D.HTM">$026D-$0276/621-630</A>     Active File Secondary Addresses
  |   <A HREF="ZP0277.HTM">$0277-$0280/631-640</A>     Keyboard Buffer Queue (FIFO)
  |   <A HREF="ZP0281.HTM">$0281-$0282/641-642</A>     Pointer: Bottom of Memory for Operating System
  |   <A HREF="ZP0283.HTM">$0283-$0284/643-644</A>     Pointer: Top of Memory for Operating System
  |   <A HREF="ZP0285.HTM">$0285/645</A>               Serial IEEE Bus timeout defeat Flag
  |   <A HREF="ZP0286.HTM">$0286/646</A>               Current Character Color code
  |   <A HREF="ZP0287.HTM">$0287/647</A>               Background Color under Cursor
  |   <A HREF="ZP0288.HTM">$0288/648</A>               High Byte of Screen Memory Address
  |   <A HREF="ZP0289.HTM">$0289/649</A>               Maximum number of Bytes in Keyboard Buffer
  |   <A HREF="ZP028A.HTM">$028A/650</A>               Flag: Repeat keys
  |   <A HREF="ZP028B.HTM">$028B/651</A>               Repeat Key: Speed Counter
  |   <A HREF="ZP028C.HTM">$028C/652</A>               Repeat Key: First repeat delay Counter
  |   <A HREF="ZP028D.HTM">$028D/653</A>               Flag: Shift Keys
  |   <A HREF="ZP028E.HTM">$028E/654</A>               Last Shift Key used for debouncing
  |   <A HREF="ZP028F.HTM">$028F-$0290/655-656</A>     Vector: Routine to determine Keyboard table
  |   <A HREF="ZP0291.HTM">$0291/657</A>               Flag: Upper/Lower Case change
  |   <A HREF="ZP0292.HTM">$0292/658</A>               Flag: Auto scroll down
  |   <A HREF="ZP0293.HTM">$0293/659</A>               RS232 Pseudo 6551 control Register Image
  |   <A HREF="ZP0294.HTM">$0294/660</A>               RS232 Pseudo 6551 command Register Image
  |   <A HREF="ZP0295.HTM">$0295-$0296/661-662</A>     RS232 Non-standard Bits/Second
  |   <A HREF="ZP0297.HTM">$0297/663</A>               RS232 Pseudo 6551 Status Register Image
  |   <A HREF="ZP0298.HTM">$0298/664</A>               RS232 Number of Bits left to send
  |   <A HREF="ZP0299.HTM">$0299-$029A/665-666</A>     RS232 Baud Rate; Full Bit time microseconds
  |   <A HREF="ZP029B.HTM">$029B/667</A>               RS232 Index to End of Input Buffer
  |   <A HREF="ZP029C.HTM">$029C/668</A>               RS232 Pointer: High Byte of Input Buffer
  |   <A HREF="ZP029D.HTM">$029D/669</A>               RS232 Pointer: High Byte of Output Buffer
  |   <A HREF="ZP029E.HTM">$029E/670</A>               RS232 Index to End of Output Buffer
  |   <A HREF="ZP029F.HTM">$029F-$02A0/671-672</A>     Temp. store for IRQ Vector during Tape I/O
  |   <A HREF="ZP02A1.HTM">$02A1/673</A>               RS232 Enables
  |   <A HREF="ZP02A2.HTM">$02A2/674</A>               TOD sense during Tape I/O
  |   <A HREF="ZP02A3.HTM">$02A3/675</A>               Temporary storage during Tape READ
  |   <A HREF="ZP02A4.HTM">$02A4/676</A>               Temporary D1IRQ Indicator during Tape READ
  |   <A HREF="ZP02A5.HTM">$02A5/677</A>               Temporary for Line Index
  |   <A HREF="ZP02A6.HTM">$02A6/678</A>               Flag: TV Standard
  |   <A HREF="ZP02A7.HTM">$02A7-$02FF/679-767</A>     Unused
  |   <A HREF="ZP02C0.HTM">$02C0-$02FE/704-766</A>     Sprite #11 Data Area
  |   <A HREF="ZP0300.HTM">$0300-$0301/768-769</A>     Vector: BASIC Error Message
  |   <A HREF="ZP0302.HTM">$0302-$0303/770-771</A>     Vector: BASIC Input Line and Decode
  |   <A HREF="ZP0304.HTM">$0304-$0305/772-773</A>     Vector: BASIC Tokenise Routine
  |   <A HREF="ZP0306.HTM">$0306-$0307/774-775</A>     Vector: BASIC LIST Routine
  |   <A HREF="ZP0308.HTM">$0308-$0309/776-777</A>     Vector: BASIC Character dispatch Routine
  |   <A HREF="ZP030A.HTM">$030A-$030B/778-779</A>     Vector: BASIC Token evaluation
  |   <A HREF="ZP030C.HTM">$030C/780</A>               Storage for 6510 Accumulator during SYS
  |   <A HREF="ZP030D.HTM">$030D/781</A>               Storage for 6510 X-Register during SYS
  |   <A HREF="ZP030E.HTM">$030E/782</A>               Storage for 6510 Y-Register during SYS
  |   <A HREF="ZP030F.HTM">$030F/783</A>               Storage for 6510 Status Register during SYS
  |   <A HREF="ZP0310.HTM">$0310/784</A>               USR Function JMP Instruction
  |   <A HREF="ZP0311.HTM">$0311-$0312/785-786</A>     USR Address
  |   <A HREF="ZP0313.HTM">$0313/787</A>               Unused
  |   <A HREF="ZP0314.HTM">$0314-$0315/788-789</A>     Vector: Hardware IRQ Interrupt Address
  |   <A HREF="ZP0316.HTM">$0316-$0317/790-791</A>     Vector: BRK Instruction Interrupt Address
  |   <A HREF="ZP0318.HTM">$0318-$0319/792-793</A>     Vector: Hardware NMI Interrupt Address
  |   <A HREF="ZP031A.HTM">$031A-$031B/794-795</A>     Vector: Kernal OPEN Routine
  |   <A HREF="ZP031C.HTM">$031C-$031D/796-797</A>     Vector: Kernal CLOSE Routine
  |   <A HREF="ZP031E.HTM">$031E-$031F/798-799</A>     Vector: Kernal CHKIN Routine
  |   <A HREF="ZP0320.HTM">$0320-$0321/800-801</A>     Vector: Kernal CHKOUT Routine
  |   <A HREF="ZP0322.HTM">$0322-$0323/802-803</A>     Vector: Kernal CLRCHN Routine
  |   <A HREF="ZP0324.HTM">$0324-$0325/804-805</A>     Vector: Kernal CHRIN Routine
  |   <A HREF="ZP0326.HTM">$0326-$0327/806-807</A>     Vector: Kernal CHROUT Routine
  |   <A HREF="ZP0328.HTM">$0328-$0329/808-809</A>     Vector: Kernal STOP Routine
  |   <A HREF="ZP032A.HTM">$032A-$032B/810-811</A>     Vector: Kernal GETIN Routine
  |   <A HREF="ZP032C.HTM">$032C-$032D/812-813</A>     Vector: Kernal CLALL Routine
  |   <A HREF="ZP032E.HTM">$032E-$032F/814-815</A>     User Defined Vector
  |   <A HREF="ZP0330.HTM">$0330-$0331/816-817</A>     Vector: Kernal LOAD Routine
  |   <A HREF="ZP0332.HTM">$0332-$0333/818-819</A>     Vector: Kernal SAVE Routine
  |   <A HREF="ZP0334.HTM">$0334-$033B/820-827</A>     Unused
  |   <A HREF="ZP033C.HTM">$033C-$03FB/828-1019</A>    Tape I/O Buffer
  |   <A HREF="ZP0340.HTM">$0340-$037E/832-894</A>     Sprite #13
  |   <A HREF="ZP0380.HTM">$0380-$03BE/896-958</A>     Sprite #14
  |   <A HREF="ZP03C0.HTM">$03C0-$03FE/960-1022</A>    Sprite #15
  |   <A HREF="ZP03FC.HTM">$03FC-$03FF/1020-1023</A>   Unused
  |
  +------------------------------------------------------------------------

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